KR100871781B1 - Co-polymer comprising imidazole based derivative, preparing method thereof, organic anti-reflective coating composition comprising the co-polymer and organic anti-reflective coating comprising the composition - Google Patents

Abstract

A copolymer containing an imidazole-based derivative, and an organic antireflective coating composition containing the copolymer are provided to improve the absorption of the exposure light reflected from the etched layer of a semiconductor substrate, the etching rate and the adhesive force to a semiconductor substrate. A copolymer containing an imidazole-based derivative comprises an imidazole-based derivative represented by the formula 1 and the structural units represented by the formulas 2 and 3 as a co-monomer, and has a weight average molecular weight of 5,000-50,000, wherein R1 is H or a methyl group; R2 is a C1-C20 alkylene group, a C1-C20 alkenylene group or a C1-C20 alkynylene group; R3 is H, a C1-C6 alkyl group substituted or unsubstituted with a hydroxyl group or a C1-C6 alkyl group substituted or unsubstituted with a C1-C3 alkoxy group; R4, R5 and R6 are independently H or a methyl group; R7 is a C1-C20 alkylene group, a C1-C20 alkenylene group or a C1-C20 alkynylene group; x is 0.1-90 mol%; y is 0.1-90 mol%; and z is 0.1-90 mol%.

Description

Copolymer comprising an imidazole derivative, a method for preparing the copolymer, an organic antireflective coating composition comprising the copolymer and an organic antireflective coating comprising the composition anti-reflective coating composition comprising the co-polymer and organic anti-reflective coating comprising the composition}

The present invention relates to a copolymer comprising an imidazole derivative, a method for preparing the copolymer, an antireflection film composition including the copolymer, and an antireflection film including the composition, and more particularly, when forming a photoresist pattern. Excellent absorption of the exposure source reflected from the layer to be etched, thereby preventing the generation of standing waves, undercut phenomenon and notching phenomenon, the copolymer production method, the composition for an organic antireflection film comprising the copolymer And it relates to an organic anti-reflection film comprising the composition.

In general, semiconductor devices operate at high speed and require a large storage capacity. Accordingly, the manufacturing technology of semiconductor devices has been developed to improve the degree of integration, reliability, and response speed. In particular, in order to improve the degree of integration of semiconductor devices, the demand for microfabrication techniques such as photolithography, which is a major technology, is becoming more stringent. In manufacturing semiconductor devices and flat panel display devices, photoresist patterns formed of photoresists are mainly used as etching masks.

Meanwhile, it is preferable to form an anti-reflective coating (ARC) before forming the photoresist film on the etching target film. This is because the anti-reflection film reduces the reflection of light on the lower etch target film when the photoresist is patterned by performing an exposure process in the photolithography process. That is, the anti-reflection film serves to prevent standing wave effects caused by interference between incident light incident on the photoresist film and reflected light reflected from the target film during exposure. In addition, the anti-reflection film serves to prevent or significantly reduce reflection due to the topography resulting from the previously formed patterns and diffuse reflection at the edges. Therefore, by forming the anti-reflection film before forming the photoresist pattern, it is possible to increase the process latitude of the semiconductor manufacturing process conditions by accurately correcting the critical width (“CD”) of the fine circuit pattern to be formed.

The antireflection film having the above-mentioned characteristics is classified into an inorganic antireflective coating layer of an inorganic material and an organic antireflection film of an organic material, depending on the composition thereof.

The inorganic antireflection film has excellent bonding characteristics with respect to the step of the lower object film. However, there is a problem in that it is not easy to remove in a subsequent process, and the formed photoresist pattern and bonding characteristics are poor.

Therefore, at present, instead of the inorganic antireflection film, an organic antireflection film which is easy to remove in a subsequent process and has excellent bonding properties with a photoresist pattern is mainly used.

The present invention is to provide a novel copolymer exhibiting better and more efficient performance under the above technical background, and its use, the object of the present invention in a photolithography process using a variety of radiation, such as KrF as an exposure source, Imidazole-based crosslinking end that has excellent absorbency of the exposure source reflected from the etched layer of the semiconductor substrate, can improve the etch rate, facilitate the formation of the organic antireflection film, and can improve the adhesion with the semiconductor substrate. To provide a copolymer containing (imidazole cross-linker) and a method for producing the same.

In addition, an object of the present invention is to provide an organic antireflection film composition comprising the copolymer and an organic antireflection film comprising the same.

In order to achieve the above object, the present invention provides a copolymer comprising an imidazole derivative represented by the following formula (1) as a monomer, the weight average molecular weight is 5,000 to 100,000.

<Formula 1>

In Formula 1, R ₁ represents hydrogen or methyl, R ₂ represents an aliphatic hydrocarbon having 1 to 20 carbon atoms, R ₃ is hydrogen or an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with a hydroxy group, or 1 to C An alkyl group having 1 to 6 carbon atoms substituted or unsubstituted with 3 alkoxy groups is shown.

In addition, the present invention is a copolymer according to claim 1, characterized in that the derivative and the initiator are dissolved in a polymerization solvent and reacted according to the radical polymerization method for 2 hours to 24 hours at a temperature of 50 to 90 ℃ in an inert gas atmosphere. It provides a method for producing.

In addition, the present invention is a copolymer; And it provides an organic anti-reflective film composition comprising an organic solvent.

The present invention also provides an organic antireflection film comprising the organic antireflection film composition.

The copolymer according to the present invention imparts a bonding force to the organic antireflection film in a photolithography process using various radiations such as KrF as an exposure source. In addition, since the absorbance of the exposure source reflected from the etched layer of the semiconductor substrate is excellent, generation of standing waves, undercutting phenomenon and notching phenomenon can be prevented. In addition, the etching rate is improved, the formation of the organic antireflection film is facilitated, and the adhesion to the semiconductor substrate is improved.

In addition, the composition for forming an organic antireflection film according to the present invention may include a light absorbing agent having excellent absorption of an exposure source in a photolithography process using various radiations such as KrF (248 nm) as an exposure source.

This has the advantage of being able to improve the adverse effects of the reflected exposure source. In addition, there is an advantage that the shrinkage stability during coating and the coating uniformity to the semiconductor substrate is excellent, and the thickness loss by the photoresist solvent is small.

Hereinafter, the present invention will be described in more detail.

One. Imidazole  Copolymers Including Derivatives

The copolymer of the present invention may be represented by the formula (1) as a copolymer containing an imidazole derivative. The copolymer is a base resin that imparts a bonding force to the organic antireflection film, and includes an imidazole derivative so that the etch rate of the organic antireflection film can be improved.

<Formula 1>

In Formula 1, R ₁ represents hydrogen or methyl, R ₂ represents an aliphatic hydrocarbon having 1 to 20 carbon atoms. R ₃ represents an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with hydrogen or a hydroxy group, or an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with an alkoxy group having 1 to 3 carbon atoms.

In the above, aliphatic hydrocarbons include alkylene groups, alkenylene groups, alkynylene groups and the like.

In addition, when R ₃ is an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with a hydroxy group or an alkyl group having 1 to 6 carbon atoms substituted or unsubstituted with an alkoxy group having 1 to 3 carbon atoms, in the heating step of the organic antireflection film manufacturing process By inducing a crosslinking reaction, the formation of the organic antireflection film can be facilitated. It is also possible to improve the adhesion with the semiconductor substrate. Specific examples of R ₃ A hydroxy ethyl group, 2-hydroxy propyl group, a methoxy methyl group, glycidyl, etc. are mentioned.

The weight average molecular weight of the copolymer of the present invention preferably has a weight average molecular weight of 5,000 to 100,000, more preferably 30,000 to 40,000, measured using gel permeation chromatography (GPC). If the weight average molecular weight is less than 5,000, the organic antireflective coating may be dissolved by the photoresist solvent. If the weight average molecular weight is more than 100,000, the organic antireflective coating composition has low solubility in a solvent and is an organic antireflective coating in a dry etching process. There is a fear that the etch rate of is lowered. On the other hand, when the weight average molecular weight is 30,000 to 40,000, the solubility in the solvent of the composition for forming an organic antireflection film is more excellent. In addition, there is an advantage in that the etching rate of the organic antireflection film is kept constant in the dry etching process.

In the copolymer of the present invention, the molar ratio of the monomer represented by Formula 1 is preferably 0.1 to 90%. The molar ratio of preferred monomers is from 5% to 80%.

The copolymer of the present invention may include two structural units represented by the following Chemical Formulas 2 and 3 together with the derivative of Chemical Formula 1 as a comonomer.

The structural unit represented by the following formula (2) is a methyl methacrylate monomer, the structural unit represented by the following formula (3) is an anthracene methyl methacrylate monomer.

<Formula 2>

<Formula 3>

In Formula 2 and Formula 3, R ₄ , R ₅ And R ₆ each independently represent hydrogen or methyl, R ₇ represents an aliphatic hydrocarbon having 1 to 20 carbon atoms, and the mole% of the total structural units of the structural units represented by Chemical Formulas 1 to 3 in the copolymer is respectively. When x, y and z are used, x is 0.1 to 90 mol%, y is 0.1 to 90 mol% and z is 0.1 to 90 mol%. Preferably x is 5 to 80 mol%, y is 5 to 80 mol%, z is 5 to 80 mol%.

For example, the copolymer may be represented by a copolymer represented by the following Structural Formula 1. At this time, each structural unit of the following structural formula 1 is not limited to the following structural formula 1 can be located at random. In addition, all of the variables described in Structural Formula 1 are the same as the variables of Chemical Formulas 1 to 3 above.

<Structure 1>

2. Imidazole  Method for producing a copolymer containing a derivative

The copolymer according to the present invention dissolves the derivative represented by the formula (1) and the initiator in a polymerization solvent, a conventional radical polymerization method for 2 to 24 hours at a temperature of 50 to 90 ℃ under an inert gas atmosphere such as nitrogen, argon, etc. The reaction can be carried out according to the present invention. When the reaction temperature is advanced to 50 to 90 ℃, it is easy to form a polymer, there is an advantage excellent in heat resistance. If the reaction time is 5 to 24 hours, the molecular weight can be easily adjusted, and the manufacturing yield is excellent.

The radical polymerization initiator is not particularly limited, but azobisisobutyronitrile (AIBN), azobisvaleronitrile (AIVN), benzoyl peroxide (BPO) and di-t-butyloxide (DTBP) which are thermal polymerization initiators. One or two or more selected from the group consisting of) may be used. Although it does not specifically limit as a solvent of the said polymerization reaction, 1 type, or 2 or more types chosen from the group which consists of dioxane, tetrahydrofuran, and benzene which are aromatic solvents can be used.

In the present invention, by adjusting the weight ratio between the monomer and the polymerization solvent or by controlling the amount of the radical initiator, a copolymer having a weight average molecular weight required in the semiconductor exposure process can be prepared.

In more detail, the preparation method may be prepared using 10 to 50 moles of the polymerization solvent and 0.01 to 0.1 moles of the initiator with respect to 1 mole of the derivative represented by Chemical Formula 1.

When the polymerization solvent is included in an amount of 10 to 50 moles with respect to 1 mole of the derivative represented by Chemical Formula 1, a copolymer having a weight average molecular weight required in the semiconductor exposure process may be prepared.

When the radical polymerization initiator is included in an amount of 0.01 to 0.1 mole based on 1 mole of the derivative represented by Chemical Formula 1, a copolymer having a weight average molecular weight required in the semiconductor exposure process may be prepared.

The polymer may also be prepared by dissolving two monomers represented by Chemical Formulas 2 and 3 together with the derivative in 1 to 8 moles, respectively, in the polymerization solvent. When each monomer is included in 1 to 8 moles with respect to 1 mole of the derivative represented by the formula (1), there is an advantage having a physical property usable as an organic antireflection film.

The weight average molecular weight of the polymer according to the present invention may be appropriately selected by those skilled in the art according to the use and the case by adjusting the polymerization conditions, and the weight average molecular weight measured using gel permeation chromatography (GPC) polystyrene conversion is 5,000 to 100,000 It is good to superpose | polymerize so that it may become. Preferably the copolymer has a molecular weight range of 30,000 to 40,000. The reason for limiting molecular weight is omitted because it has been described above.

The copolymer obtained by the same method as described above is used as the organic antireflection film material.

3. Organic Antireflection film  Composition

The organic antireflective coating composition of the present invention comprises the copolymer and the organic solvent.

The organic solvent may be used without limitation to the conventional solvent used in the semiconductor microcircuit processing process, preferably propylene glycol monomethyl ether acetate (PGMEA), ethyl 3-ethoxy propionate, ethyl having excellent coating film forming ability Lactate, methyl 3-methoxy propionate, cyclohexanone, etc. are used individually or in mixture of 2 or more types, respectively.

The copolymer is preferably included in 0.1 to 30% by weight based on the total weight of the composition. If the copolymer is included in 0.1 to 30% by weight, there is an advantage having a physical property usable as an antireflection film.

In addition, the organic solvent is preferably included in 70 to 99.9% by weight based on the total weight of the composition. When the organic solvent is included in 70 to 99.9% by weight, there is an advantage of excellent coating film formation.

In addition, an additive may be further included in the composition. Examples of the additive are not particularly limited, and examples thereof include a crosslinking reaction accelerator, a surface leveling agent, an adhesion promoter, or an antifoaming agent.

Among them, the crosslinking accelerator may be used to promote the crosslinking reaction and increase the efficiency of the reaction. One or two or more selected from the group consisting of a crosslinking agent, a stabilizer, a lower alcohol, an acid, and an acid generator may be used. Preferably, a thermal crosslinking agent, a thermal acid generator or a mixture thereof may be used. The thermal crosslinking agent is not particularly limited, but melamine-formaldehyde resin, benzoguanine-formaldehyde resin, glycoluril-formaldehyde resin, urea-formaldehyde resin, phenolic resin, benzyl alcohol, epoxy compound, isocyanate and alkoxy methyl It may be one kind or two or more kinds selected from the group consisting of melamine. The thermal acid generator is not particularly limited, but may be selected from other strong protic acids such as one or two or more selected from the group consisting of p-toluenesulfonic acid, phosphoric acid, phthalic acid, oxalic acid and dodecylbenzenesulfonic acid.

The additive is preferably included in 0.1 to 5% by weight based on the total weight of the composition. If the additive is included in more than 5% by weight, it may affect the footing or undercutting of the pattern profile by the diffusion of the additive composition.

4. Organic Antireflection film  Bottom with composition Antireflection film

The organic antireflective coating composition solution is filtered through a fine particle filtration apparatus, spun coated on a silicon wafer, and crosslinked at an appropriate temperature to obtain a desired antireflective coating. The anti-reflection film prepared in this manner serves to remove the problems caused by the reflection of light in the short wavelength far ultraviolet microcircuit processing process, so that the semiconductor device can be produced smoothly.

The copolymer including the imidazole-based crosslinked end according to the present invention shows excellent performance as an organic antireflection film for forming a microcircuit in the exposure wavelength region of short wavelength far ultraviolet rays of 248 nm, 193 nm, and 157 nm.

In addition, since it has superior adhesiveness and crosslinkability compared to the anti-reflection film based on the conventional hydroxy crosslinked groups, it has been found to be useful for the formation of ultrafine circuits when forming semiconductor devices.

Hereinafter, the present invention will be described in detail through examples. However, the embodiments are only illustrative of the present invention, and the scope of the present invention is not limited thereto.

Production Example  One. Imidazolidine Carbonyl  Methacrylate ( Imidazolidine Carbonyl  Synthesis of Methacrylate

<Scheme 1>

Dissolve 1-ethylhydroxy-2-imidazolidinone (5) (65.08 g, 0.5 mol) in 150 mL THF in a 500 mL round bottom flask equipped with a reflux condenser. At 0 ° C., methacryloyl chloride (Formula 4) (52.27 g, 0.5 mol) was slowly added and reacted for 4 hours. After the reaction, the resultant white product was obtained, and the unreacted product was separated and purified by a silica gel column, followed by pure 1-methylmethacrylate-2-imidazolidinone (1-methylmethacrylate-2-imidazolidinone: Chemical Formula 6). 80.65g (yield 83.4%) was obtained, hereinafter referred to as “ICMA”.

Production Example  2: using monomers represented by the formulas (2), (3) and (6) Terpolymer  synthesis

Anthracene methyl methacrylate (Formula 3) monomer (69.59 g, 0.25mol or less "AMMA"), ICMA (Formula 6) monomer (19.82g, 0.10mol), methyl methacrylate (Formula 2) monomer ( 65.08 g, 0.65 mol) and 0.08 mol of AIBN, a radical initiator, were dissolved in 250 ml of MEK / THF (1: 1 mixed solvent), and then polymerized at a polymerization temperature of 60 ° C. for 10 hours under a nitrogen atmosphere. The polymerization reactant was precipitated in excess methanol, and then filtered and dried to synthesize P (AMMA / ICMA / MMA), a terpolymer. The yield of P (AMMA / ICMA / MMA) obtained was 84%, with data and graphs showing the GPC results for the polymer attached to FIG. 1.

Example  1: organic Antireflection film  Preparation of the composition

According to the components and the composition ratios shown in Table 1 below to prepare an organic antireflection film composition. In more detail, the copolymer was dissolved in an organic solvent, an additive was added thereto, stirred, and filtered through a microporous membrane filter to prepare a bottom anti-reflective coating composition.

Copolymer (% by weight) Additive (% by weight) Organic solvent (% by weight) Example 1 a-1 3.5 b-1 0.1 c-1 96.4

a-1: the copolymer prepared in Preparation Example 2

b-1: aminoplast (trade name, manufacturer: Aldrich Corporation)

c-1: propylene glycol monoether (manufacturer: Aldrich Co., Ltd. <Aldrich Co., Ltd.))

Test Example  One: Organic anti-reflective coating  Manufacture and evaluation

The organic antireflection film composition of Example 1 was spin-coated on a silicon wafer and crosslinked at 100 ° C. to 250 ° C. for 10 to 120 seconds to prevent intermixing with photoresist to be formed in a later step. Thereafter, the photoresist was spin-coated on the cured organic antireflection film, and soft baked at 80 ° C. or 120 ° C. for 30 to 120 seconds to remove the remaining solvent, and then exposed through a 100 nm level photomask. 2.38 wt% tetramethyl After the development process for 20 to 100 seconds using an alkaline developer such as ammonium hydroxide (TMAH), the results as shown in Table 2 are described.

Undercutting Putting CD change of pattern Pattern profile Example 1 ○ ○ ○ ○

CD changes in undercutting, footing, and pattern:

◎: Never occurs ○: 1 to 5% occurs

△: 5 to 10% occurs ×: defective

Pattern profile: ◎: Very good ○: Excellent △: Normal ×: Poor

Referring to Table 2, it can be seen that the organic anti-reflective coating prepared using Example 1 according to the present invention exhibits fine undercutting, footing, and CD change of the pattern, and the pattern profile is excellent.

1 shows GPC results for polymers prepared according to Preparation Example 2 of the present invention.

Claims (15)

An air containing an imidazole derivative represented by Formula 1 below and an imidazole derivative comprising 2 structural units represented by Formulas 2 and 3 as comonomers and having a weight average molecular weight of 5,000 to 50,000. coalescence: <Formula 1>

<Formula 2>

<Formula 3>

In Chemical Formulas 1 to 3, R ₁ represents hydrogen or methyl, R <_2> represents a C1-C20 alkylene group, a C1-C20 alkenylene group, and a C1-C20 alkynylene group. R ₃ represents an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with hydrogen or a hydroxy group, or an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with an alkoxy group having 1 to 3 carbon atoms, R ₄ , R ₅ and R ₆ each independently represent hydrogen or a methyl group, R <_7> represents a C1-C20 alkylene group, a C1-C20 alkenylene group, and a C1-C20 alkynylene group. In the copolymer, when mole% of the entire structural units of the structural units represented by Chemical Formulas 1 to 3 are x, y and z, respectively, x is 0.1 to 90 mole%, y is 0.1 to 90 mole%, and z is 0.1-90 mol%. delete For 1 mole of a derivative represented by Formula 1, Dissolve 1 to 8 mol and 0.01 to 0.1 mol of initiator in each of the two structural units represented by Formula 2 and Formula 3 in 10 to 50 mol of a polymerization solvent, Reacted according to the radical polymerization method for 2 to 24 hours at a temperature of 50 to 90 ° C. under an inert gas atmosphere, The initiator is selected from the group consisting of azobisisobutyronitrile (AIBN), di-t-butyloxide (DTBP), acetyl peroxide (APO), benzoyl peroxide (BPO) and azobisvaleronitrile (AIVN). 1 or 2 or more selected Method for producing a copolymer according to claim 1, wherein the polymerization solvent is one or two or more selected from the group consisting of dioxane, tetrahydrofuran and methyl ethyl ketone: <Formula 1>

<Formula 2>

<Formula 3>

In Chemical Formulas 1 to 3, R ₁ represents hydrogen or methyl, R ₂ represents an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 1 to 20 carbon atoms, an alkynylene group having 1 to 20 carbon atoms, R ₃ represents an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with hydrogen or a hydroxy group, or an alkyl group having 1 to 6 carbon atoms unsubstituted or substituted with an alkoxy group having 1 to 3 carbon atoms, R ₄ , R ₅ and R ₆ each independently represent hydrogen or a methyl group, R <_7> represents a C1-C20 alkylene group, a C1-C20 alkenylene group, and a C1-C20 alkynylene group. delete delete delete delete delete 0.1 to 30% by weight of the copolymer according to claim 1; And 70 to 99.9 wt% of an organic solvent, The organic solvent is one selected from the group consisting of butyrolactone, propylene glycol monomethylether acetate, ethyl 3-ethoxy propionate, ethyl lactate, methyl 3-methoxy propionate, and cyclohexanone, or Organic antireflection film composition, characterized in that two or more. delete delete The method according to claim 9, The organic antireflection film composition further includes an additive, The additive is an organic antireflection film composition, characterized in that one or two or more selected from the group consisting of crosslinking reaction promoters, surface leveling agents, adhesion promoters and antifoaming agents. delete The method according to claim 12, An organic antireflection film composition comprising the additive in an amount of 0.1 to 5% by weight based on the total weight of the composition. An organic antireflection film comprising the organic antireflection film composition according to claim 9.

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